Substrate for upscaled mushroom production was developed by investigating over 20 substrate mixes based on original (not separated into liquid and solid fraction) combined food waste—diary ma-nure digestate and straw of 4 different Norwegian grains in Phase I and II composting. Investigation of 6 different mushroom species resulted in two best suitable for cultivation on this substrate: Almond but-ton and Pink Oyster mushrooms. Different combinations of organic materials (including spent mush-room substrates) were tested for plant cultivation including green waste compost and vermicompost (GVC). The best in terms of physical and chemical properties and were chosen for subsequent experi-ments with plant cultivation. Cherry tomato was selected based on the best performance on GVC. Composting earthworms were beneficial in a growing system fertilised with digestate (digeponics). Yield, plant aboveground biomass and root biomass of tomatoes grown in medium with earthworms were similar to peat based commercial growing medium. Dry matter content of tomatoes was higher in digeponic than control. Combined cultivation of mushrooms and plants can be performed in the same container. The mushroom: Almond mushroom and plants: cucumber and Cowpea were most promis-ing combinations. To decrease cultivation waste from both mushroom and plant production, spent cul-tivation substrate (SCS) from performed experiments was recycled. To evaluate if the recycled SCS can be further reused as a new growing medium or growing medium additive for vegetables, subsequent mushroom cultivation several chemical and physical features were measured. The assessment recom-mended composting or co-composting with additional waste products to eliminate potential pests and because of high mineral salt contents. SCSs exhibit good composting potential with a sufficiently high C/N ratio and organic matter content (50–65%) to heat up during composting. Good-quality compost from food and other organic wastes is rich in valuable nutrients, which can be recycled back into food production by its use as an excellent soil amendment.
Circulation of elements from cultivation substrates to mushroom crops was assessed by indicating the bioaccumulation factor (BCF) of more than 60 elements, proving that cultivation on digestate is safe for human consumption. Elemental concentration in mushrooms showed 24 elements were effectively accumulated from substrate to mushrooms of both Agaricus species. Content of determined elements in mushrooms was nevertheless below estimated daily intake (EDI), thus consumption of mushrooms grown on digestate can be considered as safe for human health. Pink oyster mushrooms effectively ac-cumulated 11 elements and can serve as an excellent source of Ca, Mg and Na, Mn, Mo, Ni and Se and Zn. Specification of the profile of 14 phenolic compounds and 9 organic acids showed that both Agari-cus mushrooms are good source of 6 of the organic acids. Almond mushroom was richer in phenolic acids than common button mushroom.
The project has over its duration been disseminated on 10 conferences and fairs, 5 peer reviewed, open access scientific articles has already been published, 3 more are in preparation. Communication to the different target groups were held with 6 presentations, workshops, and seminar, 1 more is planned for 2023, 5 press releases. One start-up advisory and mushroom producing company, SOPPAS, emerged from the action. Action is communicated in social media (4), project websites (2).
